Your garden may have been done by now. But here's my bit of inspiration for you. Presuming your desire to keep path is because it is the entry to your house. 1. All along the front boundary, planting a living screen/hedge edged garden bed ... Murraya Panniculata (Flowers have tropical orange blossom scent) 2. The garden bed (under window) on the left hand side of path to become your tropical oasis of planting - consider mass for extra drama and lights along pathway leading to door. 3. Other side - the right hand side pathway ... Using width of "porch/pillar"area as guide, create an edged new garden bed and plant it up to your heart'[s content with tropical style, and in front of that and up to the Murrraya Panniculata hedging pave and create a usable courtyard - with table and chairs to enjoy a breakfast, or afternoon tea - and why not include a daybed for reading pleasure? 4. Imagine the view into the garden area from inside!!

I agree with asquithoatley. If you want to keep the central lawn then the concrete around the sides is the obvious area to address. Along the house the path accesses the clothesline and the sitting area. Along the metal fence it seems to do very little except obstruct the potential for a lusher more private more inviting space. Towards the view I feel like I would do something to cover that balustrade because at the moment it seems to provide a good view of a rooftop, but perhaps that's just the photo.

I agree a hard charcoal surface may overheat, and no matter what the hard surface (unless you go for ceramic tile) it will absorb urine and retain the smell. I've always had big dogs and have experienced similar problems. I solved the digging by laying wire mesh (chicken wire) on all flat surfaces and then covering with pine bark. The dogs quickly grew tired of digging when they had no success. Dogs often dig to create a hole to lie in to stay cool. Make sure they have plenty of shade. I'd consider also incorporating some artificial turf and training them to toilet on that.

So many great suggestions here for you! What a fabulous house to work with. I would extend the pergola out to where the BBQ is, but scrap it. I also suggest replacing the brick paved area with large creamish pavers & use the bricks to pave the path in a bit if a curve. Utilize the curved area for seating widening the steps as suggested. A couple of large pots with citrus either side. These could be planted later as the garden progresses. Also a grape vine or wisteria planted to grow over the pergola would give summer shade & let light into the house in winter. I would screen the granny flat with either a few hardy bushes or a lattice type screen & grow a passion-fruit, kiwi fruit or climbing rose. If you don't like the climbing thing something structural like yucca's or cordylines, both low maintenance - talk to your local nursery, they are the experts. They may offer garden design too. Also have a look at http://plantselector.botanicgardens.sa.gov.au/ Just put in your postcode & you get a list of plants with pictures, descriptions etc. Enjoy your garden room. Good luck.